Skin is subject to insults by many extrinsic and intrinsic factors. Extrinsic factors include ultraviolet radiation (e.g., from sun exposure), environmental pollution, wind, heat, low humidity, harsh surfactants, abrasives, and the like. Indeed, one of the key elements, if not the primary element, responsible for accelerated skin aging is overexposure to the sun's harmful rays. Intrinsic factors include chronological aging and other biochemical changes from within the skin. Whether extrinsic or intrinsic, these factors result in visible signs of skin aging and environmental damage, such as lines, wrinkling and other forms of surface roughness (including increased pore size, cracking, and flaking) as well as other histological changes associated with skin aging and damage. While extrinsic concerns such as photoaging can be slowed with the use of moisturizers, sunscreens and avoidance of sun exposure, these solutions cannot address the more important and complex causes of skin aging associated with the intrinsic factors. The elimination of lines and wrinkles, combined with a general increased tautness and youthful appearance of skin, has become a booming business in youth-conscious societies. Treatments range from cosmetic creams and specialized moisturizers to various forms of cosmetic surgery.
Perhaps the key underlying physiological change in aging skin is a thinning and general degradation of the skin, most notably a degradation and/or loss of various cells and/or chemical constituents necessary for maintaining the physiological characteristics of youthful skin. Specifically, as the skin naturally ages, the division rate of skin cells slows down causing an overall reduction in the number of cells and blood vessels that supply nutrients and other necessary building blocks for the skin and resulting in a significant decrease in the thickness of the epidermis. Concurrently, as the skin ages proteins, especially collagen and elastin fibers in the underlying layers of skin which provide the scaffolding for the surface layers, begin to weaken and deteriorate and/or manifest a deterioration in their cross-linking capabilities causing the skin to lose elasticity as well as resulting in a flattening of and concurrent loss of mechanical properties, including strength and flexibility, particularly, but not exclusively, in the dermal-epidermal junction (Neerken S, Lucassen G W, Bischop M A, Lenderink E, Nuijs T A, J Biomed Opt. 2004 March-April; 9(2):274-81 and Oikarinen, “The Aging of Skin: Chronoaging Versus Photoaging,” Photodermatol. Photoimmunol. Photomed., vol. 7, pp. 3-4, 1990, both of which are incorporated by reference herein in their entirety).
The dermal-epidermal junction (DEJ) is a critical component of the skin and is composed of a network of structural proteins that provide a firm connection between the basal keratinocytes of the epidermis and the dermis. This structural network is made up of (1) the hemidesmosome-anchoring filament complex; (2) the basement membrane comprising two layers, the lamina lucida and the lamin densa, and (3) anchoring fibrils. The lamina lucida is a thinner layer and lies directly beneath the epidermal layer of basal keratinocytes. The thicker lamina densa is in direct contact with the underlying dermis. The basal keratinocytes are connected to the basement membrane via the hemidesmosome-anchoring complex and the basement membrane, in turn, is connected to the dermis via the anchoring fibrils. Each of these components of the DEJ has specific constituents, most notably laminins, integrins tenascin, and above all collagens, specifically collagen IV, and a very precise role to play (Allen J., Br. J. Dermatol. 1997 December; 137 (6): 907-15), (M. Aumailley, Kidney Internat., Vol 47, Suppl. 49 (1995), pp S-4-S-7). Concurrently, these structures are the target of immunologic injury in bullous pemphigoid and epidermolysis bullosa.
The upper surface of the dermis is characterized by dermal papillae containing a plexus of capillaries and lymphatics extending from the papillary dermis perpendicular to the skin surface. These fingerlike projections are surrounded by similar, opposing projections of the epidermis extending from the basal keratinocytes in an interdigitate orientation. Intermediate these fingerlike projections is the dermal epidermal junction layer which, consequently, takes on an undulating character. This highly irregular junction greatly increases the surface area over which the exchange of oxygen, nutrients, and waste products occurs between the dermis and the avascular epidermis. Concurrently, this undulating characteristic combined with the aforementioned anchoring structures ensure cohesion between the dermis and epidermis and accommodates the mechanical deformation of the skin, e.g., as the skin is pulled and stretched, the DEJ will flatten out without loss of cohesion and then return to its normal state as the tension pulling the skin is released. For all these reasons, the DEJ has a very important role to play from a metabolic and mechanical standpoint for the good health of the skin. However, as the skin ages, the quality of the DEJ tends to diminish, most notably as manifested by a flattening of the DEJ, whereby its “undulating shape” drops dramatically, reducing the surface area interchange as well as the elasticity in the skin. (B. Le Varlet et al. Journal of Investigative Dermatology Symposium Proceedings 3: 172-179, 1998). A reduced surface interchange results in a progressive loss of nutrients to the DEJ and the epidermis which, in turn, slows the circulation of the messengers that serve to promote the neo-synthesis process of collagen. Without an optimal amount of collagen, the skin sags even more, propagating the dearth of nutrients. Paradoxically, matured aging skin contains more elastin, which the body uses to fill in the empty space left by the deficiency of collagen. Such elastin is fragmented, calcified, and contains excessive lipids. In addition to the loss of skin thickness due to the lack of collagen support, the aging or aged skin is looser and lacks elasticity. These two properties are the hallmarks of wrinkles and creases.
The important role of the DEJ is also applicable to metabolic diseases when one of the components of the DEJ is absent or of poor quality. For example, bullous pemphigoid is characterized by the absence of laminin-5 which deficiency leads to a detachment of the epidermis from the dermis and the resultant formation of blisters which develop into sores that are difficult to heal. Similarly, psoriasis has been shown to involve molecular and structural alterations of the DEJ arising from an adverse impact on the cytomorphological processes and the normal functions of the basement membrane (Vaccaro M, Pergolizi S, Mondello R, Santoro G, Cannavo S P, Guarneri B, Magauddal L, Archives of Dermatological research, 291(7-8):396-399, 1999).
Numerous efforts have been undertaken for improving the dermal-epidermal junction resulting in a number of successful, at least to some extent, techniques having been developed. Representative disclosures in this area include:                Marionnet et. al. have shown the utility of vitamin C in improving the DEJ formation in an in vitro human reconstructed skin model leading to a DEJ structure closer to that of normal young looking human skin (Marionnet C, Vioux-Chagnoleau C, Pierrard C, Sok J, Asselineau D, Bernerd F, Meeting abstracts, 34th Annual European Society for dermatological Research Meeting, September 2004, Vinenna, Austria).        Fisher et. al. have shown an improvement in the DEJ formation and extracellular matrix proteins arising from retinoids (Fischer G J and Voorhees J J, Molecular mechanisms of retinoid actions in skin. FASEB J. 10, 1002-1013 (1996).        Varani et. al. have shown vitamin A as antagonizing decreased cell growth and elevated collagen-degrading matrix metalloproteases while concurrently stimulating collagen accumulation in naturally aged human skin, Varani J, et. al., J Investigative Dermatology, 114:480-486, 2000).        
Numerous investigations have shown the beneficial impact of topical applications of retinoids on skin appearance as well as on various histological parameters such as a thickening of the epidermis including the stratum granulosum, an increase in the height of epidermal ridges or retes of the DEJ and the number of dermal papillae, a gradual displacement of age-related deposition of dermal elastin by collagen and peptidoaminoglycans, normalization of melanocyte function and an increase in the number of dermal fibroblasts. See, for example, Kligman, U.S. Pat. Nos. 4,603,146 and 4,877,805; Zelickson, A. S., J. Cutaneous Aging Cosmet. Dermatol., 1:4147 (1988); Weiss, J. S., JAMA, 259:527-532 (1988); J. Bhawan, Arch. Dermatol., 127:666-672 (1991); and Kligman, L. H., Connect. Tissue Res., 12:139-150 (1984).                Dyer et. al. (U.S. Pat. No. 7,351,745) teach a method of applying a physiologically effective amount of an active agent, wherein said active agent is S-Methyl-L-Cysteine and S-Phenyl-L-Cysteine in a dermatologically pharmaceutically or physiologically acceptable vehicle, sufficient to increase expression levels of at least one gene selected from the group consisting of: Beta-catenin, Collagen 4, Collagen 7, Frizzled 10, Estrogen Receptor alpha, Hyaluronic acid synthase, and combinations thereof and for improving the condition and appearance of skin.        Bernerd (US Patent Application: 2004/0005342) teaches the use of ascorbic acid or an analogue thereof in a pharmaceutically or cosmetically acceptable medium, to increase the synthesis of tenascin and/or collagen VII for reinforcing the cohesion at the DEJ.        Dal Farra et. al. (U.S. Pat. No. 7,211,269) teach a method for preparing cosmetic or dermatological compositions of a sufficient amount of peptides of sequence (Gly-Pro-Gln)n-NH2, wherein: n ranges between 1 and 3, and wherein the amino acids can be in the form L, D or DL, the compositions being designed to promote adhesion between skin cells, promote cell adhesion, to provide curative and/or preventive treatment for aging skin symptoms (of physiological or solar origin) and to enhance skin appearance. In a preferred embodiment, the peptide is of sequence (Gly-Pro-Gln)2-NH2.        Bonte et. al. (U.S. Pat. No. 6,641,848) teach the use of saponins or sapogenols, particularly those extracted from plants such as soya or Medicago, in cosmetology and for the manufacture of pharmaceutical compositions for treating the skin in order to increase the amount of collagen IV in the dermal-epidermal junction.        Paufique (U.S. Pat. No. 6,531,132) describes a process for extracting an active principle from yeast whereby the active principle is used to retard the degradation of the dermal-epidermal junction to improve the surface condition of the skin.        Dumas et. al. (U.S. Pat. No. 6,495,147) describes the use of D-xylene, esters thereof or oligosaccharides containing D-xylose for stimulating the synthesis and/or secretion of proteoglycans and/or glycosaminoglycans by the keratinocytes of a human in need thereof.        Bonte et. al. (U.S. Pat. No. 6,471,972) teaches a cosmetic treatment method for fighting against skin aging effects wherein the method comprises the application of at least one agent for promoting the adhesion of the keratinocytes of the epidermal basal layer to the dermal-epidermal junction, especially to the collagen IV of said junction, such as, in particular, a divalent metal salt or complex, preferably magnesium aspartate or magnesium chloride, optionally in association with a stimulant of collagen IV synthesis and/or a stimulant of collagen VII synthesis.        LeSquer et. al. (WO 2002/015869) described combinations of ursolic acid and/or oleanolic acid with a specific palmitoyl pentapeptide Lys-Thr-Thr-Lys-Ser as synergistically increasing/stimulating the neosynthesis of compounds of the DEJ including collagen IV.        
Despite all the efforts that have been undertaken to formulate effective compositions for improving the dermal-epidermal junction, current products are not entirely effective. Vitamin C and some of its derivatives are not photochemically or hydrolytically stable. In certain environments, especially in the presence of iron and hydrogen peroxide, Vitamin C can act as a pro-oxidant. Retinoids are very effective, but they also suffer from stability problems. Additionally, retinoids can also cause skin irritation, sensitization and are teratogenic. Plant extracts, if not standardized against key actives, oftentimes are not effective. Peptides are effective, but not fully characterized as yet. For example, though not manifest in short term use, some minor peptide impurities may cause adverse effects over long-term use. Consequently, the user oftentimes finds themselves with no results or an undesired result, e.g., irritation, sensitization, burning sensation, erythema, etc. of the skin.
Alternative approaches to improving the condition or appearance of aging skin that have received increasing attention involve the modulation of extracellular matrix proteins and matrix degrading enzymes and transcription factors. Representative disclosures in this area include:                Mancini A, Di Battista J A, “Transcriptional regulation of matrix metalloprotease gene expression in health and disease”, Front Biosci, 11:423-446, 2006.        S Reitamo, A Remitz, K Tamai, and J Uitto, “Interleukin-10 modulates type I collagen and matrix metalloprotease gene expression in cultured human skin fibroblasts”, Cin Invest, 1994, 94(6):2489-2492, 1994 von Marcschall Z, Riecken E O, Rosewicz S, “Induction of matrix metalloprotease-1 gene expression by retinoic acid in the human pancreatic tumour cell line Dan-G”, Br J Cancer, 80(7):935-939, 1999.        Bair E L, Massey C P, Tran N L, Borchers A H, Heimark R L, Cress A E, Bowden G T, “Integrin- and cadherin-mediated induction of the matrix metalloprotease matrilysin in cocultures of malignant oral squamous cell carcinoma cells and dermal fibroblasts”, Exp Cell Res, 270(2):259-267, 2001.        Nagahara S, Matsuda T, “Cell-substrate and cell-cell interactions differently regulate cytoskeletal and extracellular matrix protein gene expression”, J Biomed Mater Res, 32(4):677-86, 1996        Smits P, Poumay Y, Karperien M, Tylzanowski P, Wauters J, Huylebroeck D, Ponec M and Merregaert J, “Differentiation-Dependent Alternative Splicing and Expression of the Extracellular Matrix Protein 1 Gene in Human Keratinocytes”, J Invest Dermatol, 114:718-724, 2000.        Reunamen N, Westermarck J, Hakkinen L, Holmstrom, Elo I, Eriksson J E, Kahari V M, “Enhancement of fibroblast collagenase (matrix metalloproteinase-1) gene expression by ceramide is mediated by extracellular signal-regulated and stress-activated protein kinase pathways”, J Biol Chem, 273(9):5137-45, 1998.        McKay I A, Winyard P, Leigh I M, Bustin S A, “Nuclear transcription factors: potential targets for new modes of intervention in skin disease”, Br J Dermatol, 131(5):591-597, 1994.        
Liping Du, Neis M M, Ladd P A, and Keeney D S, “Differentiation-Specific Factors Modulate Epidermal CYP1-4 Gene Expression in Human Skin in Response to retinoic Acid and Classic Aryl Hydrocarbon Receptor Ligands” Journal of Pharmacology And Experimental Therapeutics Fast Forward First published on Sep. 19, 2006; DOI: 10.1124/jpet.106.111724).
Despite these advances, there is still a huge need and demand for, and, in following, a tremendous level of research and development effort being expended for, skin care/treatment compositions that are more effective and more forgiving; especially those that are able to provide anti-aging effects. However, in contrast to early efforts, a more fundamental and comprehensive approach is needed for treating aging skin that is based on the biology of the skin. As noted above, skin aging is a natural phenomenon that occurs over time and is not just a result of wear and tear, but is also the consequence of a continually active genetic program that might be up- or down-regulated resulting in detrimental effects on skin. Again, as noted above, aging results in a flattening of the DEJ, a slow down of the division rate of skin cells, a slow down in the production of collagen, and defective cross-linking of collagen and elastin fibers in the skin, among other adverse consequences. Thus, from a biological standpoint, an effective anti-aging strategy for improving the condition and appearance of skin must include rejuvenation of skin cells at both the epidermal and the dermal layers, increased levels of proteins in the dermal-epidermal junction, up-regulation of cell adhesion molecules, protection of the rejuvenated cells and cellular activity, stimulation of the production of skin matrix proteins, down-regulating transcription factors responsible for adverse effects to skin cells and detection and repairing of DNA damage. Biologically based components such as large molecular weight proteins cannot be used topically as they are unable to cross the skin barrier or orally as they tend to quickly degrade in the presence of proteolytic enzymes. Other compounds, such as the retinoids, while effective, have poor stability and at high levels, especially on a continual basis, can be poisonous, even lethal, and result in other adverse consequences including skin sensitization and irritation. Thus, an effective anti-aging composition must readily penetrate through the skin permeability barrier and/or resist biodegradability when taken orally while also having excellent stability with minimal, if any, adverse toxicological effects when used on a continual basis.
Surprisingly, it has now been found that certain naturally derived compounds, as well as their synthetic counterparts, are effective skin care/treatment compositions providing many, if not most, of the desired attributes of the utopian, or nearly utopian, skin care/treatment composition.
Additionally, according to the present invention there is provided a new and effective method for ameliorating, reducing and/or reversing the adverse consequences of skin aging, as well as certain adverse consequences of extrinsic factors, such as sun damage, through the application of a gene manipulating effective amount of these compounds.
Finally, there is provided a new method for preventing or slowing down the adverse consequences of skin aging through the continual application of a gene manipulating effective amount of these compounds.